Valproic acid is one of the most widely used antiepileptic drugs. To be effective as a remedy, the concentration of valproic acid in the blood vessels must be kept within a suitable range. Ineffective treatment may occur if the treatment dosage is too low. Even worse, adverse effects may occur if the treatment dosage is too high. Therefore, the concentration of the valproic acid in the blood vessels is very important.
The size of the instruments used to monitor the concentration of valproic acid may be large. Thus, the monitoring instruments may not be portable and their prices may be very expensive. Consequently, patients cannot immediately determine whether or not the concentration of the drug in their blood vessels is within the optimal range for effective treatment.